DESCRIPTION: The goal of this study is to study directional hearing in fish, using the sleeper goby as the model. It has five aims: 1. Determine the structural polarity of sensory hair cells in each otolithic organ in 3D space using LEM and SEM. 2. Determine if individual end organs play differential roles in encoding sound direction along different planes. 3. Make structure-function relationships by dye-filling ganglion cells from which directional sensitivity had been assessed by intracellular recordings. 4. Identify any particular direction in which the fish is particularly sensitive and measure MAAs. 5. Determine the contribution of each end organ to the pattern of directional hearing.